The continental crust

Seventy-seven major components of the North American continent were delineated at a general scale (1:5,000,000); including the general composition, geological environment, and types of primary metals endowments that can be expected in each domain.

Prospect- and mine-related features on USGS topographic maps

Symbols indicating mining-related features digitized from historical USGS topographic maps in the western part of the conterminous US. Includes prospect pits, mine shafts and adits, quarries, open-pit mines, tailings piles and ponds, gravel and borrow pit